Regardless of industry structure, a firm positions itself in the best profit-maximizing level of production if that amount of output reflects the point at which the last unit's marginal revenue is equal to its marginal cost. Why? Multiple select question. Total revenue is greatest by producing after the quantity determined by the MR = MC rule. Each unit of output prior to the MR = MC rule earns more revenue for the firm than its costs. Total revenue is greatest at amounts prior to the MR = MC amount. Each unit of output after the MR = MC amount will earn less revenue than its costs